HL-LHC IR Higher Order Corrector Magnets Conceptual Design & Construction Activity F. Alessandria, G. Bellomo, F. Broggi, A. Paccalini, D. Pedrini, A.Leone, M. Quadrio, L. Somaschini, M. Sorbi, M. Todero, C. Uva INFN Milano, LASA Lab. P. Fessia, E. Todesco CERN Presented by Giovanni Volpini KEK, 20 November 2014 V 20 11 b
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HL-LHC IR Higher Order Corrector Magnets Conceptual Design & Construction Activity F. Alessandria, G. Bellomo, F. Broggi, A. Paccalini, D. Pedrini, A.Leone,
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HL-LHCIR Higher Order Corrector Magnets
Conceptual Design & Construction Activity
F. Alessandria, G. Bellomo, F. Broggi, A. Paccalini, D. Pedrini, A.Leone, M. Quadrio, L. Somaschini, M. Sorbi, M. Todero, C. Uva
INFN Milano, LASA Lab.
P. Fessia, E. TodescoCERN
Presented by Giovanni Volpini
KEK, 20 November 2014
V 20 11 b
Giovanni Volpini KEK 20 November 2014
1. 2D & 3D electromagnetic design
2. magnet coupling
3. magnet construction & technological developments
4. organization, next steps, conclusion
1. 2D & 3D electromagnetic design
2. magnet coupling
3. magnet construction & technological developments
4. organization, next steps, conclusion
outline
Giovanni Volpini KEK 20 November 2014
Corrector magnet inventory
From 6-pole to 12-pole magnets exist in both normal and skew form (the latter is shown)
150
OD320
150
OD460
The superferric design was chosen for ease of construction, compact shape, modularity, following the good performance of earlier corrector prototype magnets developed by Ciemat (Spain).
High Precision Zone for harmonics computation boundary
Yoke radius = 230 mm
HX bore D 60 mm @ r = 185 mm
Jeng (overall) ~ 300 A/mm²
Bpeak coil = 2.97 T
Giovanni Volpini KEK 20 November 2014
0.0 0.1 0.2 0.3 0.4
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0I c A
0 1 2 3 4B T 0
10 000
20 000
30 000
40 000
50 000
60 000
At Aturns
Design integrated strength 0.086 T∙m
Desig
n o
pera
tin
g
cu
rren
t ra
tio v
s.
s.s
. lim
it (
40%
)
shortsamplelimit
Operatingcurrent
n.o. turns
peak field @s.s. limit
peak field @ operating current
Integrated B6 [T·m]
Load line & optimization procedure
Dodecapole shown as example
Giovanni Volpini KEK 20 November 2014
Symmetricflux return plate
round bore flux return plate
Iron yoke total length 801 mm
HX hole D60 @ r = 185 mm
Flux Return PlatesYo
ke
Bri
dge
Giovanni Volpini KEK 20 November 2014
Iron yoke half length
Flu
x re
turn
No flux return plate
symmetric flux return plateround
hole fluxreturn plate
Stray Field
Giovanni Volpini KEK 20 November 2014
3D computations COMSOL™ OPERA™ Roxie
No FRYIntegrated B3 @ r = 50 mm T·m -0.0758 -0.0759 -0.0756
b9 10-4 -21.50 -21.57 -22.5
With FRYIntegrated B3 @ r = 50 mm T·m
-0.0686 -0.0688not
computedb9 10-4 -1.494 -1.444
A Comparison of Codes
Use different codes to simulate the same sextupole, to cross-check & validate the results:• COMSOL + Mathematica for harmonic analysis• OPERA (2D and 3D models developed by Alejandro Sanz-Ull, CERN-TE-MSC)• Roxie
2D computations: agreement within few parts/104 on fields; ~ 1/10 of unit on relevant harmonics.
Giovanni Volpini KEK 20 November 2014
-4
-3
-2
-1
0
1
2
3
0 100 200 300 400
Un
its [
1e-4
]
Operating current [A]
2D
3D a6
3D b6
Iop 120.4
-25
-20
-15
-10
-5
0
5
10
0 50 100 150 200 250 300
un
its a
2 [
1E-4
] I op [A]
quadrupole a2
2D
3D
Harmonics vs. operating current
-1
0
1
2
3
4
5
6
7
8
9
0 50 100 150 200 250 300
Un
its [
1e-4
]
Operating current [A]
2D 3D
decapole a5/ b5
Iop 139.1
Iop 166 A (b6) 172 A (a6)
Differential Inductance, a6
10 000 20 000 30 000 40 000 50 000
0 .02
0 .04
0 .06
0 .08
0 .10
0 .12
0 .14
Operating pointLd = 52 mH
«zero-current» inductance, from linear-iron case, L = 149 mH
Ampere·turns [At]
Indu
ctan
ce [H
]
26
3/I
II
Ld(I) = 1/I dU/dI = ns2 / At dU/d At
Giovanni Volpini KEK 20 November 2014
Giovanni Volpini KEK 20 November 2014
1. 2D & 3D electromagnetic design
2. magnet coupling
3. magnet construction & technological developments
4. organization, next steps, conclusion
Giovanni Volpini KEK 20 November 2014
Problem statement
Coupling: electromagnetic cross-talk and forces acting between adjacent corrector magnets.
A full (2π) model has been developed since in the most general case no symmetry exists. One magnet is powered, with real iron and the second one (coupled) is described through its iron yoke, assuming linear iron. Loose boundary conditions and the «mixture» of different problems (high field, current driven on one side, and «quasi magnetostatic» on the other), led to convergence problem and doubtful solutions.
A simplified model has therefore been introduced, leaving out the iron yoke and considering only the flux return yoke and the bridge of second magnet. This increases the symmetry of the problem (only π /n is now required), reducing computation time/increasing the accuracy, at the price of a somewhat less accurate description of the second magnet.
We have considered two cases: quadrupole and octupole
Giovanni Volpini KEK 20 November 2014
Modelsource magnet: current yoke+bridge+FRY real iron
Round-hole FRY
coupled magnet:no currentonly FRY + bridge simulated linear iron µr = 4000
Box for Maxwell e.m. stress tensor calculation
dyoke bridge
flux return yoke
FRY bridge
The magnetic induction in the FRY of the coupled magnet is mostly concentrated close to the bore, and is extremely small in the bridge connecting the FRY to the yoke (the latter is not modelized)
Case d = 10 mm
Giovanni Volpini KEK 20 November 2014
Cross-talk in the coupled magnet
B in the coupled magnet as a function of the separation: octupole
earth magnetic flux density
Flux density in the coupled magnet FRY and bridge decreases exponentially with increasing separation between magnets. We can assume that the value in the yoke is even smaller, leading to a negligible excitation of the magnet.
Cross check:Iron replaced w/ air in the second magnet
Giovanni Volpini KEK 20 November 2014
Nominal separation between iron yokes: 76.44 mm
octupole
Giovanni Volpini KEK 20 November 2014
B in the coupled magnet as a function of the separation:
quadrupole
Nominal separation between iron yokes:76.44 mm
FRY w/ 3 platesempty symbols
FRY w/ 2 plates (standard case)full symbols
quadrupole
Giovanni Volpini KEK 20 November 2014
1 Integration of the Maxwell stress tensor (MST) on the surface of an air volume sourrounding the iron. In this case, we are interested in the net (external) force, so we neglected the surface on the ϱ-z planes;2 An internal feature of COMSOL, which is based also on the Maxwell stress tensor;3 Virtual work principle.
Computation of the force between iron yokes turned out to be harder than expected.Following methods were exploited:
Forces between magnets I
1 was computed considering a surface in air encompassing the iron of the second magnet;Despite we do not know precisely how 2 works (COMSOL documentation explains that MST is integrated on the relevant surface, but it is unclear how this is precisely accomplished, since some components of B and H are not continuous across the iron surface), the results of 2 agree with 1 to within ±3%.3 requires in our case knowledge of the energy with ppm (or ppb!) accuracy, which is unrealistic. Still it can be used to set an upper bound on the forces.
1E-5
1E-4
1E-3
1E-2
1E-1
1E+0
1E+1
0 20 40 60 80
Tota
l fo
rce [
N]
Distance [mm]
Forces between magnets II
a4/b4
a2
1415.98
1416.00
1416.02
1416.04
1416.06
1416.08
0 50 100
Sto
red
En
erg
y [
J]
Distance between iron [mm]
ΔU < 0.1 J
Fz(z1) < 0.1 J/0.02 m = 5 N
25022.9
25023.0
25023.1
25023.2
25023.3
0 20 40 60 80 100
Sto
red
En
erg
y [
J]
Distance between iron [mm]
ΔU < 0.4 JFz(z1) < 0.4 J/0.033 m = 12 N
quadrupole
Attractive force decreases exponentially, the higher orders the faster.F(z) = F(0) e -(z/λ)
λ ≈ 33 mm (quadrupole)λ ≈ 20 mm (octupole)
If ΔU is an upper bound for the stored energy variation changing the separation by Δz = z2 - z1, an upper bound for the attractive force is given by
F(z1) < ΔU/ λ ; λ < Δz F(z1) < ΔU/ Δz ; λ > Δz
octupole
Nominal separation between iron yokes: 76.44 mm
Giovanni Volpini KEK 20 November 2014
Giovanni Volpini KEK 20 November 2014
1. 2D & 3D electromagnetic design
2. magnet coupling
3. magnet construction & technological developments
4. organization, next steps, conclusion
Giovanni Volpini KEK 20 November 2014
Bruker-EAS NbTi for Fusion applicationFine filaments ITER PF wireWire type 2Cu:NbTi ≈ 2.30Number of filaments 3282Filament diameter≈ 8 μm @ 0.73 mmTwo wire diameters: 0.5 and 0.7 mmS2-glass insulation, 1 km batch of 0.5mm deliveredWaiting for the delivery of 8 km + 8 km
Luvata PoriOK3900 Cu:NbTi ≈ 2.00Number of filaments 3900wire diameter 0.575 mm Filament diameter≈ 5.3 μmBare wire20 km delivered
- Small wire (low operating current), but not too small (must be easy to handle, insulation should not reduce too much the Je)
- High Cu content(again, low operating current, 4-pole protection)
- Off the shelf product: small amount required (10’s of kg)
- Small filament: not a strict requirement, but these magnets are designed to operate in the whole range 0-Imax
SC wire
Giovanni Volpini KEK 20 November 2014
Yoke laminations machined by laser cutfollowed by EDM (final accuracy 1/100 mm) on the relevant surfaces: poles, coil slots, alignment slots.
5.8 mm thick iron laminations, supplied by CERN
Sextupole preliminary design 320
123
891
460
Design
Giovanni Volpini KEK 20 November 2014
Tool for winding & impregnation
Giovanni Volpini KEK 20 November 2014
Giovanni Volpini KEK 20 November 2014
Insulation scheme:-wire w/ S2 glass 0.14 mm thick (on dia)-ground insulation: G11, 2 mm thick plates on both sides of the coil, include the wire exits G11 thin, flexible layer on the inner wall of the coil; S2 tape on the outer wall
Coil tooling
Giovanni Volpini KEK 20 November 2014
winding and impregnationWinding machine:
Commercial winding machine;
Home-developed braking system, electrical synchronous motor controlled by a variable frequency inverter regulating the wire tensioning between 1 and 20 kg ;
Oven
CTD 101 K resin system
Temperature monitored with a PT100 on the mould, in agreement within +/- 1°C wrt the set temperature (in stationary conditions)
Giovanni Volpini KEK 20 November 2014
«Coil 1» under the optical
measuring machine
ID 510
3000
Giovanni Volpini KEK 20 November 2014
Test station The LASA magnet test station will be used for the magnet cold test. An existing cryostat will be used for the test of sextupole to skew dodecapole.
Fast and slow data acquisition are now being adapted for the new test. A new QDS is now being built.
A new cryostat, to be fit inside the exsisting magnet test station at LASA, has been designed to test 4-pole. This allows to use the exsisting services (current, LHe feed and GHe recovery, signal, etc.)
Giovanni Volpini KEK 20 November 2014
1. 2D & 3D electromagnetic design
2. magnet coupling
3. magnet construction & technological developments
4. organization, next steps, conclusion
MAGIX & INFN participation to HL-LHC
29
MAGIX
WP1 CORRAL
Design, construction and test of
the five prototyes of the
corrector magnets for the HL
interaction regions of HiLUMI
WP2PADS
2D & 3D engineering design of
the D2 magnets
WP3 SCOW-2G
Development of HTS coil for
application to detectors and
accelerators
WP4 SAFFO
Low-loss SC development for
application to AC magnets
MAGIX is a INFN-funded research project, (GrV, «Call») whose goal is to develop superconducting technologies for application to future accelerator magnets.It includes four WP’s, two of which are relevant to HL-LHC2014-2017, 1 M€ + personnel funds (all WP’s)
Approved by the INFN Board of Directors & signed by INFN President on June 2014; signed by CERN DG on July 17th.CERN endorses MAGIX WP1 & WP2 deliverables and milestones, contributing with 527 k€
Giovanni Volpini KEK 20 November 2014
Giovanni Volpini KEK 20 November 2014
Sextupole Residual magnetization at I=0 and impact on the harmonics ~Feb 15 Executive design Jan 15
Sextupole Construction & test Cryostat for the sextupole test commissioned Jan 15 QDS and slow and fast data acquisition adapted Feb 15 Order to workshop for mechanical components manufacture Feb 15 Sextupole assembled May 15 Sextupole tested June 15
Other design Executive design octupole to dodecapole Nov 15 MgB2 quadrupole design completed. Dec 15
Next Steps
Giovanni Volpini KEK 20 November 2014
Conceptual design from quadrupole to dodecapole concluded
Attractive forces between nearby magnets << 1 newton; cross-talk negligible
Executive design of the sextupole started
Superconducting wire delivery to be completed soon
Winding & impregnation tests in progress
Test preparation in progress, in view of the sextupole test in 2015
D 1.1a Mar 2014 * Preliminary 2D design of the five magnet typesD 1.1b Mar 2015 * Preliminary 3D design of the five magnet types
D 1.2 Oct 2016 Executive design of the five magnet typesM 1.3 Dec 2015 ** MgB2 quadrupole design.
M 1.4a Mar 2016 *** Octupole and decapole constructionM 1.4b Jul 2016 *** Quadrupole and dodecapole construction
M 1.5 Oct 2016 MgB2 quadrupole constructionM 1.6a Apr 2015 **** Test of the sextupoleM 1.6b July 2016 **** Test of the octupole and decapoleM 1.6c Feb 2017 **** Test of the dodecapole and quadrupole
D 1.3 Mar 2017 Corrector magnet test reportD 1.4 June 2017 Corrector magnets final check, packing and transport to CERN
WP2M 2.1 D 2.1 June 2015 2D magnetic design to minimize the cross talk between the two dipoles.
M 2.2 D 2.2 Dec 2015 2D mechanical design.
M 2.3 Feb 2016 3D magnetic design including the coil ends.
M 2.4 Apr 2016 Quench preliminary analysis.
M 2.5 Jun 2016 3D mechanical design with the axial pre-load study.
M 2.6 D 2.3 Dec 2016 Final Engineering design.
Notes Explanation* These two deliverables are grouped in one in the MAGIX project Activity
** Note the change of scope wrt to the MAGIX project*** These two milestones are grouped in one in the MAGIX project Milestone
**** These two milestones are grouped in one in the MAGIX projectDeliverable
2017
CORRAL
PADS
2014 2015 2016
Project Management
INFN-CERN Agreement approved by INFN board of directors in June ‘14, to be signed by INFN President
D 1.1a Mar 2014 * Preliminary 2D design of the five magnet typesD 1.1b Mar 2015 * Preliminary 3D design of the five magnet types
D 1.2 Oct 2016 Executive design of the five magnet typesM 1.3 Dec 2015 ** MgB2 quadrupole design.
M 1.4a Mar 2016 *** Octupole and decapole constructionM 1.4b Jul 2016 *** Quadrupole and dodecapole construction
M 1.5 Oct 2016 MgB2 quadrupole constructionM 1.6a Apr 2015 **** Test of the sextupoleM 1.6b July 2016 **** Test of the octupole and decapoleM 1.6c Feb 2017 **** Test of the dodecapole and quadrupole
D 1.3 Mar 2017 Corrector magnet test reportD 1.4 June 2017 Corrector magnets final check, packing and transport to CERN
WP2M 2.1 D 2.1 June 2015 2D magnetic design to minimize the cross talk between the two dipoles.
M 2.2 D 2.2 Dec 2015 2D mechanical design.
M 2.3 Feb 2016 3D magnetic design including the coil ends.
M 2.4 Apr 2016 Quench preliminary analysis.
M 2.5 Jun 2016 3D mechanical design with the axial pre-load study.
M 2.6 D 2.3 Dec 2016 Final Engineering design.
Notes Explanation* These two deliverables are grouped in one in the MAGIX project Activity
** Note the change of scope wrt to the MAGIX project*** These two milestones are grouped in one in the MAGIX project Milestone
**** These two milestones are grouped in one in the MAGIX projectDeliverable
2017
CORRAL
PADS
2014 2015 2016
Project Management
Giovanni Volpini KEK 20 November 2014
MilestonesM 1.1 Sextupole engineering design completed. July 2014M 1.2 Sextupole construction completed. December 2014M 1.3 MgB2 quadrupole design completed. December 2015M 1.4.a Octupole and decapole construction completed. March 2016M 1.4.b Quadrupole and dodecapole construction completed. July 2016M 1.5 MgB2 quadrupole construction completed October 2016M 1.6.a Sextupole test April 2015M 1.6.b Octupole and decapole test. July 2016M 1.6.c Quadrupole and dodecapole test. February 2017
DeliverablesD 1.1a Preliminary 2D design of the five magnets, from quadrupole to dodecapole March 2014D 1.1b Preliminary 3D design of the five magnets, from quadrupole to dodecapole. March 2015D 1.2 Executive design of the five magnets, from quadrupole to dodecapole. October 2015 D 1.3 Test report (…) with the tests results performed on the corrector magnets March 2017D 1.4 Magnet Corrector magnet prototypes for all the five types, cold tested and qualified. June 2017
It does not include:
the warm and cold magnetic characterization (harmonic analysis);the cryostat and its mechanical connections;the mechanical and electrical interconnections between the magnets themselves and the rest of the machine;the realization of the series, composed of a total of 48 magnets of various types.